Earlier research has found that preoperative experience with partial reinforcement (PR) can reverse the usual deficit in responding for food reward on lean schedules that typically follows VMH lesions. However, pilot data suggests that this effect may depend upon the type of reinforcement employed. The first part of the present reinforcement on responding for food by rats with VMH lesions. The second part of the study will determine - 1) whether VMH lesions affect the mag- nitude of the frustration effect (FE) in the Amsel double runway and 2) whether preoperative experience with partial reinforcement attenuates the magnitude of the FE.